Expanding a fluorescent RNA alphabet: synthesis, photophysics and utility of isothiazole-derived purine nucleoside surrogates.

A series of emissive ribonucleoside purine mimics, all comprised of an isothiazolo[4,3-d]pyrimidine core, was prepared using a divergent pathway involving a key Thorpe-Ziegler cyclization. In addition to an adenosine and a guanosine mimic, analogues of the noncanonical xanthosine, isoguanosine, and 2-aminoadenosine were also synthesized and found to be emissive. Isothiazolo 2-aminoadenosine, an adenosine surrogate, was found to be particularly emissive and effectively deaminated by adenosine deaminase. Competitive studies with adenosine deaminase with each analogue in combination with native adenosine showed preference for the native substrate while still deaminating the isothiazolo analogues

Influence of accidental over‐polarisation on the mechanical properties of cathodically protected pre‐tensioned tendons

This paper investigates the performance of pre‐tensioned tendons deliberately exposed to higher than normal impressed current cathodic protection (ICCP) to replicate accidental over‐polarisation. Plain ungalvanised tendons, 5.4 mm Ø, were pre‐stressed in moulds and cast in mortar. Two levels of pre‐tensioning were investigated, low (~30% ultimate tensile strength [UTS]) and high level (~80% UTS). Three different degrees of corrosion with target losses of cross‐sectional area of 0%–1%, 2%–4% and 4%–7%, respectively, were employed to replicate in situ conditions. ICCP was applied to the tendons at two levels of polarisation, normal protection (ICCP‐N) in the range of −650 to −750 mV and overprotection (ICCP‐O) ranging between −850 and −1300 mV, both versus Ag/AgCI/0.5‐M KCI for an extended period. After ICCP, the tendons were removed from the mortar and slow strain tensile tests were conducted. The results show that ICCP at both normal and overprotection had no significant influence on the elastic modulus, yield, 0.2% proof stress and ultimate strength of the tested tendons. Although ductility was reduced, fracture occurred after reaching the ultimate strength

Red light-emitting Carborane-BODIPY dyes: Synthesis and properties of visible-light tuned fluorophores with enhanced boron content

A small library of 2,6- and 3,5-distyrenyl-substituted carborane-BODIPY dyes was efficiently synthesized by means of a Pd-catalyzed Heck coupling reaction. Styrenyl-carborane derivatives were exploited as molecular tools to insert two carborane clusters into the fluorophore core and to extend the π-conjugation of the final molecule in a single synthetic step. The synthetic approach allows to increase the molecular diversity of this class of fluorescent dyes by the synthesis of symmetric or asymmetric units with enhanced boron content. The structural characterization and the photoluminescence (PL) properties of synthesized dyes were evaluated, and the structure/properties relationships have been investigated by theoretical calculations. The developed compounds exhibit a significant bathochromic shift compared to their parent fluorophore scaffolds, and absorption and emission patterns were practically unaffected by the different substituents (Me or Ph) on the Ccluster atom (Cc) of the carborane cage or the cluster isomer (ortho- or meta-carborane). Remarkably, the presence of carborane units at 2,6-positions of the fluorophore produced a significant increase of the emission fluorescent quantum yields, which could be slightly tuned by changing the Cc-substituent and the carborane isomer, as well as introducing ethylene glycol groups at the meso-position of the BODIPY

Straight motion of half-integer topological defects in thin Fe-N magnetic films with stripe domains

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Flutuação de esporos de Plasmopara vitícola em cultivo protegido de videira.

o uso da cobertura plástica (CP) no cultivo de videiras pode apresentar vantagens no ganho em qualidade das uvas, protegendo çle prejuizos causados por granizos e doenças fúngicas. O mildio da videira (P/asmopaf'8 vilico/a) é a' doença fúngica com maior importância no que diz respeito à incidência e gastos com aplicações de fungicidas. A modificação microclimática que a CP pode exercer sobre o vinhedo, sobretudo pela eliminação da água livre sobre folhas e cachos, contribui para a diminuição de incidência e severidade de doenças fúngicas de forma geral.Resumo